def test3(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.00001 | units.AU**2
instance.dt_dia = 5000
stars = datamodel.Stars(2)
star1 = stars[0]
star2 = stars[1]
star1.mass = units.MSun(1.0)
star1.position = units.AU(numpy.array((-1.0,0.0,0.0)))
star1.velocity = units.AUd(numpy.array((0.0,0.0,0.0)))
star1.radius = units.RSun(1.0)
star2.mass = units.MSun(1.0)
star2.position = units.AU(numpy.array((1.0,0.0,0.0)))
star2.velocity = units.AUd(numpy.array((0.0,0.0,0.0)))
star2.radius = units.RSun(100.0)
instance.particles.add_particles(stars)
for x in range(1,2000,10):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
stars.savepoint()
instance.cleanup_code()
instance.stop()
def test1(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
hermite = Hermite(convert_nbody)
hermite.initialize_code()
hermite.parameters.epsilon_squared = 0.0 | units.AU**2
hermite.parameters.end_time_accuracy_factor = 0.0
hermite.dt_dia = 5000
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
hermite.particles.add_particles(stars)
hermite.evolve_model(365.0 | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
position_at_start = earth.position.value_in(units.AU)[0]
position_after_full_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostRelativeEqual(position_at_start, position_after_full_rotation, 6)
hermite.evolve_model(365.0 + (365.0 / 2) | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostRelativeEqual(-position_at_start, position_after_half_a_rotation, 3)
hermite.evolve_model(365.0 + (365.0 / 2) + (365.0 / 4) | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation = earth.position.value_in(units.AU)[1]
self.assertAlmostRelativeEqual(-position_at_start, position_after_half_a_rotation, 3)
hermite.cleanup_code()
hermite.stop()
def test2(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.dt_dia = 5000
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
for x in range(1, 500, 10):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
stars.savepoint()
if HAS_MATPLOTLIB:
figure = pyplot.figure()
plot = figure.add_subplot(1,1,1)
x_points = earth.get_timeline_of_attribute("x")
y_points = earth.get_timeline_of_attribute("y")
x_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), x_points)
y_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), y_points)
plot.scatter(x_points_in_AU,y_points_in_AU, color = "b", marker = 'o')
plot.set_xlim(-1.5, 1.5)
plot.set_ylim(-1.5, 1.5)
test_results_path = self.get_path_to_results()
output_file = os.path.join(test_results_path, "hermite-earth-sun2.svg")
figure.savefig(output_file)
instance.cleanup_code()
instance.stop()
def test2(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.dt_dia = 5000
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
for x in range(1, 500, 10):
instance.evolve_model(x | units.day)
instance.particles.copy_values_of_all_attributes_to(stars)
stars.savepoint()
if HAS_MATPLOTLIB:
figure = pyplot.figure()
plot = figure.add_subplot(1,1,1)
x_points = earth.get_timeline_of_attribute("x")
y_points = earth.get_timeline_of_attribute("y")
x_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), x_points)
y_points_in_AU = map(lambda (t,x) : x.value_in(units.AU), y_points)
plot.scatter(x_points_in_AU,y_points_in_AU, color = "b", marker = 'o')
plot.set_xlim(-1.5, 1.5)
plot.set_ylim(-1.5, 1.5)
test_results_path = self.get_path_to_results()
output_file = os.path.join(test_results_path, "hermite-earth-sun2.svg")
figure.savefig(output_file)
instance.cleanup_code()
instance.stop()
def test10(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.parameters.stopping_conditions_number_of_steps = 10
self.assertEquals(instance.parameters.stopping_conditions_number_of_steps,10)
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
instance.stopping_conditions.number_of_steps_detection.enable()
instance.evolve_model(365.0 | units.day)
self.assertTrue(instance.stopping_conditions.number_of_steps_detection.is_set())
instance.particles.copy_values_of_all_attributes_to(stars)
instance.cleanup_code()
instance.stop()
def test10(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
instance = Hermite(convert_nbody)
instance.initialize_code()
instance.parameters.epsilon_squared = 0.0 | units.AU**2
instance.parameters.stopping_conditions_number_of_steps = 10
self.assertEquals(instance.parameters.stopping_conditions_number_of_steps,10)
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
instance.particles.add_particles(stars)
instance.stopping_conditions.number_of_steps_detection.enable()
instance.evolve_model(365.0 | units.day)
self.assertTrue(instance.stopping_conditions.number_of_steps_detection.is_set())
instance.particles.copy_values_of_all_attributes_to(stars)
instance.cleanup_code()
instance.stop()
def test20(self):
convert_nbody = nbody_system.nbody_to_si(1.0 | units.MSun, 149.5e6 | units.km)
hermite = Hermite(convert_nbody)
hermite.initialize_code()
hermite.parameters.epsilon_squared = 0.0 | units.AU**2
hermite.parameters.end_time_accuracy_factor = 0.0
hermite.parameters.is_time_reversed_allowed = True
stars = self.new_system_of_sun_and_earth()
earth = stars[1]
hermite.particles.add_particles(stars)
hermite.evolve_model(365.0 | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
position_at_start = earth.position.value_in(units.AU)[0]
position_after_full_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostRelativeEqual(position_at_start, position_after_full_rotation, 6)
hermite.evolve_model(365.0 - (365.0 / 2) | units.day)
hermite.particles.copy_values_of_all_attributes_to(stars)
position_after_half_a_rotation_backward = earth.position.value_in(units.AU)[0]
self.assertAlmostRelativeEqual(-position_at_start, position_after_half_a_rotation_backward, 4)
hermite.evolve_model(365.0 | units.day)
position_at_start = earth.position.value_in(units.AU)[0]
position_after_full_rotation = earth.position.value_in(units.AU)[0]
self.assertAlmostRelativeEqual(position_at_start, position_after_full_rotation, 6)
hermite.cleanup_code()
hermite.stop()
def make_effective_iso_potential_plot(gravity):
"""
This function is copied from the amuse documentation.
The last part has been altered to also plot our Moon Earth system
and the test particles orbit.
"""
omega = (constants.G * gravity.particles.total_mass() /
(5.0 | units.AU**3)).sqrt()
center_of_mass = gravity.particles.center_of_mass()[:]
plt.rcParams.update({'font.size': 30})
figure = plt.figure(figsize=(12, 12))
ax = plt.gca()
ax.get_yaxis().get_major_formatter().set_useOffset(False)
ax.minorticks_on()
current_axes = plt.subplot(1, 1, 1)
current_axes.set_aspect("equal", adjustable="box")
lim = 6e5
potential = effective_iso_potential_plot(gravity,
omega,
xlim=[-lim, lim] | units.km,
ylim=[-lim, lim] | units.km,
center_of_rotation=center_of_mass,
fraction_screen_filled=0.85)
# Simulation towards the Moon
position = [329931, 0, 0] | units.km # position of the lagrange point
velocity = [0.14, 1.022, 0] | units.kms # these parameters worked well
gravity.particles.add_particles(create_testparticle(position, velocity))
x, y, E_begin, E_end = integrate_orbit(
1.85, gravity) # towards the moon 1.85 days is sufficent
#initialize integrator
converter = nbody_system.nbody_to_si(1.0 | units.MSun, 1.0 | units.AU)
gravity = Hermite(converter)
gravity.particles.add_particles(Earth_Moon_system())
gravity.particles.add_particles(create_testparticle(position, velocity))
gravity.particles.velocity = gravity.particles.velocity * -1.
x2, y2, E_begin2, E_end2 = integrate_orbit(
10, gravity) # towards the Earth 10 days is sufficient
# make numpy arrays
x = np.array(x)
y = np.array(y)
x2 = np.array(x2)
y2 = np.array(y2)
# Make plot
plt.scatter([0], [0], color='b', s=25, label='Earth')
plt.plot(x[1], y[1], color='r', lw=2, label='Moon')
plt.plot(x[2], y[2], color='k', lw=2, label='Test particle')
plt.plot(x2[1], y2[1], color='r', lw=2)
plt.plot(x2[2], y2[2], color='k', lw=2)
plt.legend(fontsize=12)
# Plot langrangian point
plt.scatter(329931, 0, marker='+', s=30, zorder=2, c='m')
plt.text(329931, -31306, "$L_1$", size=20, zorder=3, color='m')
# Stop integrator
gravity.cleanup_code()
gravity.stop()
# Label and show
xlabel('x')
ylabel('y')
plt.ticklabel_format(style='sci', axis='both', scilimits=(0, 0))
plt.tight_layout()
plt.savefig("lagrange_points.png")
plt.show() # show figure
